The present invention relates to an integral hydraulic valve and cylinder assembly for power steering marine drive applications. The invention is suitable for use with marine drives that are steered or turned to alter the course of a boat. Such marine drives may typically comprise an inboard/outboard stern drive or an outboard motor.
A power steering assembly for a marine drive employs a hydraulic assist to reduce steering loads to the operator. The steering arm of the marine drive is connected to the piston rod of a hydraulic cylinder, and the housing of the cylinder in turn is anchored to the boat. The steering wheel of the boat is connected through a steering cable to a movable valve that controls the direction and flow magnitude of the hydraulic fluid provided to the hydraulic cylinder. The operator of the boat thus needs only to exert enough effort to operate the valve and not that required to actually steer the boat.
Heretofore power steering systems for marine drives such as that shown in U.S. Pat. No. 3,450,087 have utilized separate valve and cylinder components. This has required hydraulic connections between the discreet components and mounting brackets for each of the components both of which result in considerable additional cost to the marine drive.
U.S. Pat. No. 3,631,833 shows a power steering mechanism for a marine drive in which the valve is located at the end of the cylinder. However, such a mechanism is rather complex and includes a steering cable that extends coaxially through the cylinder rod to operate the valve.